# -*- coding: utf-8 -*-
#
# Copyright 2017 Ricequant, Inc
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.


class Positions(dict):
    def __init__(self, position_cls):
        super(Positions, self).__init__()
        self._position_cls = position_cls
        self._cached_positions = {}

    def __missing__(self, key):
        if key not in self._cached_positions:
            self._cached_positions[key] = self._position_cls(key)
        return self._cached_positions[key]

    def get_or_create(self, key):
        if key not in self:
            self[key] = self._position_cls(key)
        return self[key]
